1. Field of the Invention
The present invention relates to a method for producing metal nanoparticles, an ink composition using the same, and a method for producing the same, and more particularly, to a method for producing metal nanoparticles having surface stability, excellent adhesion, and a crack reducing effect by modifying the substituents of metal nanoparticles, an ink composition using the same, and a method for producing the same.
2. Description of the Related Art
Since a noncontact direct writing technology using an inkjet printer can discharge a fixed amount of ink to an exact location, it has the advantages of saving on material costs and shortening production time.
For the industrial applications of the inkjet printer, there is a need to develop ink suitable for the inkjet printer. As a result, in order to develop materials for inkjet printing, research into a method capable of mass-producing metal particles at low cost has been frequently conducted.
As the recent interest in solar cells is increased, a demand for ink and paste containing silver nanoparticles having excellent electrical characteristics has sharply increased.
A wet particle synthesizing method has an advantage in that the synthesized metal particles have a high yield; however, capping the surfaces of particles with various types of dispersants is required in order to secure the stability of particles. In connection with this problem, a method for producing metal particles using a fatty acid or an aliphatic amine around metal has been developed in the related art. The method for capping the silver nanoparticles with the fatty acid has excellent stability after producing ink, but causes cracks after sintering and has weak adhesion with a substrate. As a result, the method has many drawbacks as an electronic material. On the other hand, the method for capping the silver nanoparticles with the aliphatic amine has excellent characteristics as an electronic material due to a lower crack generation rate and strong adhesion with a substrate, but has the drawback of degrading the stability of particles.
Therefore, in order to synthesize metal nanoparticles having both an amine and an acid, when synthesizing the metal nanoparticles by inputting both an amine and an acid at the same time, an amide is produced due to the reaction of the amine and the acid, which exists in a synthesis solution as a type of an organic matter difficult to wash.